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Friday, 29 November 2013

Plain or simple indexing

Universal or plain or simple indexingPoints : what is Universal or plain or simple indexingSimple or universal indexing is accomplished by mean of a mechanism. Universal or
plain indexing is a method of indexing for number beyond the range of rapid indexing
in this operation, the index head spindle is moved by turning an index crank attached
to a worm which meshes with the worm wheel. The worm wheel has 40 teeth and a
worm has a single start thread. For, each turn of the index crank, the worm wheel
moves one tooth or 1/40 of a revolution. To cause the spindle to make turn, the index
crank must take 40 turns or in other words the ratio between the revolution of the
index crank and those of the spindle is 40: 1 (The ratio of worm and worm wheel is 40 :
1). A wide range of divisions may
be indexed by using this method. The Brown and Sharp Company supplies 3 plates
with the following hole circle.